I don't think so. The HVAC system is aided by the high pressure zone behind the windshield. Like @Ultramaroon , you'll just get gunk in your HVAC system. If you have the blower motor going, it's going to have pretty good flow already at max setting.

One thing that I didn't think about but did notice at a recent track day was that if you have hood vents, you car is likely going to suck in the hot engine exhaust air. The HVAC intake is the grating on the windshield cowl on the driver side. I was wondering why it seemed hotter than ambient during some points of my drive :sigh:

New driver cooling ducts to be tested this weekend at Portland on my STI.
$7 each side in downspout parts at Lowes.

https://bl6pap004files.storage.live....&cropmode=none...https://bl6pap004files.storage.live....&cropmode=none

lol, was looking for something a bit more integrated but beggars can't be choosers I suppose!

At this point I am thinking naca duct in the roof. Track car anyway so eff it :burnrubber:

I think our corner windows are a little too small to get airflow in compared to what can be replaced in a Spec Miata, buttt I'm thinking with some ingenuity and customization + 3D printing something could be made at a smaller scale, but I guess at what cost for looks? The drain spout is pure function and cheap, but probably not my favorite choice either

I think you are right about the air flow over the 1/4 window. My first attempt at a duct was a failure as it did not direct any air into the car. I realized that the A pillar and mirror interfered with the flow of air across the 1/4 window. A NACA duct needs unobstructed air flow to work.


https://connect.xfinity.com/appsuite...ain&width=1024

Hey Kelse! Funny running into you on the forums (we met at ECR). You're now officially not allowed to laugh if I zip tie a gutter drain to my car :lol:

My gutter downspouts worked pretty well. There was flow into the car, but not a hurricane. I think an extension on the front would probably improve the flow even more.

So as an update, BSP made this as a solution for the DS and I just had them make one for the passenger side it worked so well. Lots of airflow.

https://i.imgur.com/FdyOjeZ.jpg
https://i.imgur.com/9Uyy84w.jpg
https://i.imgur.com/WDsolLe.jpg
https://i.imgur.com/2EztJiw.jpg


Only thing I'm pondering is removing the rear "sail" glass. I'm thinking it would help air flow more. If not, I'm going to remove the factory vents/bleeder flap things in the rear to help get negative pressure behind the seats.

this gives me some pretty terrible idea's about making an old-style window that can flip around in that area...

It flows a lot of air. It made a big difference. There's just NO AIRFLOW in that car.

The more I think about it, the more I think it's because of a lack of an exit for the air rather than needing ducting.

Yeah, you need a spot at a low pressure area of the body to evacuate the air from the cabin. Vent at license plate position on trunk?

Careful! Vent location at the base of the rear hatch was a major fail for the first year 240Z. I spent years sucking exhaust gasses whenever I didn't force fresh air into the cabin.

Didn't even think of that. Good point.